Spacer for double-glazing units, and double-glazing unit

ABSTRACT

A spacer for a double-glazing unit, and a double-glazing unit, which make it possible to improve the durability performance of the double-glazing unit and moreover are capable of housing a granular desiccant in the spacer. The double-glazing unit  10  is comprised of a pair of glass plates  11  and  12  each of thickness 3.0 mm that face one another with a predetermined gap therebetween, a spacer  13  that is inserted between the glass plates  11  and  12  at a peripheral portion thereof so as to fix the predetermined gap between the glass plates  11  and  12  at, for example, 14.5 mm, and a secondary sealant  16  that is filled between the glass plates  11  and  12  on the outside of the spacer  13  and seals the spacer  13  from the exterior. The spacer  13  is comprised of an elongated thin-walled hollow body  13   b  that is interposed via a primary sealant  15  between the pair of glass plates  11  and  12  in the double-glazing unit  10  and houses a desiccant  13   a . The hollow body  13   b  has, at a side thereof facing onto the hollow layer  14  formed inside the double-glazing unit  10 , an overlapping portion  13   d  where overlap occurs in a direction perpendicular to mutually facing surfaces of the pair of glass plates  11  and  12.

RELATED APPLICATIONS

This is a continuation of International Application No.PCT/JP2004/017634, filed on Nov. 19, 2004, which claims priority fromJapanese application no. 2003-389633 filed Nov. 19, 2003.

TECHNICAL FIELD

The present invention relates to a spacer for double-glazing units, anda double-glazing unit, and in particular to a spacer for double-glazingunits, and a double-glazing unit, that can be used in the constructionfield in residential and non-residential buildings and so on, and thetransport field in automobiles and other vehicles, ships, aircraft andso on.

BACKGROUND ART

Hitherto, as shown in FIG. 4, a double-glazing unit 40 has asubstantially rectangular spacer 44 having an approximately rectangularcross-sectional shape joined via a joining material 43 between a pair ofglass plates 41 and 42 in the double-glazing unit 40. The spacer 44 doesnot have a free end, and thus cannot open and close.

Moreover, as shown in FIG. 5, another double-glazing unit 50 iscomprised mainly of a pair of glass plates 51 and 52 each of thickness 5mm that face one another with a predetermined gap therebetween, a spacer54 that is inserted between the glass plates 51 and 52 at a peripheralportion thereof so as to fix the predetermined gap between the glassplates 51 and 52 at, for example, 6 mm, and a curable resin sealant 55that is filled in between the glass plates 51 and 52 on the outside ofthe spacer 54 and seals the spacer 54 from the exterior. The spacer 54has a stainless steel rigid separating member 56 having a substantiallyU-shaped cross section that is joined via a joining material 57 betweenthe pair of glass plates 51 and 52 in the double-glazing unit 50. Therigid separating member 56 has housed therein a moisture-permeable resinlayer 53 as a desiccant (see, for example, Japanese Laid-open PatentPublication (Kokai) No. H11-107644, Japanese Laid-open PatentPublication (Kokai) No. H04-250285).

However, with the double-glazing unit 40, deformation of the pair ofglass plates 41 and 42 occurs through changes in internal pressureaccompanying changes in the temperature of a hollow layer 45 formedinside the double-glazing unit 40, and yet deformation of the spacer 44hardly occurs. There is thus a problem of the joining material 43joining between the spacer 44 and each of the pair of glass plates 41and 42 undergoing expansion and contraction, whereby the joiningmaterial 43 becomes thinner or breaks, and hence the resistance of thedouble-glazing unit 40 to penetration of moisture into the hollow layer45 is markedly reduced, bringing about a drop in the durabilityperformance of the double-glazing unit 40.

Moreover, with the other double-glazing unit 50, thinning or breakage ofthe joining material 57 can be suppressed through the first spacer 54deforming, but a special adhesive desiccant must be housed in the spacer54, it not being possible to house an ordinary granular desiccant in thespacer 54.

The present invention has been devised in view of the problems describedabove. It is an object of the present invention to provide a spacer fora spacer for double-glazing units, and a double-glazing unit, which makeit possible to improve the durability performance of the double-glazingunit and moreover are capable of housing a granular desiccant in thespacer.

DISCLOSURE OF THE INVENTION

To attain the above object, in an aspect of the present invention, thereis provided a spacer for a double-glazing unit joined via joiningportions between a pair of glass plates in the double-glazing unit, thespacer comprising an elongated thin-walled hollow body housing adesiccant, wherein the hollow body has, at a side thereof facing onto ahollow layer formed inside the double-glazing unit, an overlappingportion where overlap occurs in a direction perpendicular to mutuallyfacing surfaces of the pair of glass plates.

In the present invention, the hollow body has a substantiallyrectangular cross-sectional shape.

In the present invention, the cross-sectional shape of the hollow bodyprojects out at a side thereof opposite the overlapping portion.

In the present invention, the side opposite the overlapping portion inthe cross-sectional shape of the hollow body projects out toward anouter periphery of the double-glazing unit.

In the present invention, a gap at the overlapping portion is not morethan 0.6 mm.

In the present invention, a length of the overlapping portion in athickness direction of the double-glazing unit is not more than a valueobtained by subtracting 2.0 mm from an inside dimension of the hollowbody in the thickness direction of the double-glazing unit.

In the present invention, the hollow body contains aluminum or an alloyhaving aluminum as a principal component thereof.

In the present invention, the hollow body has a thickness of at least 2mm.

Moreover, in the present invention, there is provided a double-glazingunit having therein a spacer for a double-glazing unit according to thepresent invention.

In the present invention, the double-glazing unit has a sealing portionthat is filled between the pair of glass plates on the outer peripheryside of the double-glazing unit relative to the spacer, and seals thespacer from the exterior.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a double-glazing unit body havingtherein a spacer for a double-glazing unit according to an embodiment ofthe present invention;

FIGS. 2A and 2B are fragmentary sectional views of the double-glazingunit 10 shown in FIG. 1; specifically:

FIG. 2A is a fragmentary sectional view of an outer peripheral portionof the double-glazing unit 10; and

FIG. 2B is an enlarged fragmentary sectional view of the outerperipheral portion of the double-glazing unit 10;

FIG. 3 is a graph showing the relationship between a primary sealantstrain ratio and a double-glazing unit lifetime ratio;

FIG. 4 is a sectional view of a conventional double-glazing unit; and

FIG. 5 is a sectional view of another conventional double-glazing unit.

BEST MODE FOR CARRYING OUT THE INVENTION

The present inventors carried out assiduous studies to attain the aboveobject, and as a result discovered that in the case of a spacer for adouble-glazing unit interposed via joining portions between a pair ofglass plates in a double-glazing unit, if the spacer is comprised of anelongated thin-walled hollow body housing a desiccant, and the hollowbody has, at a side thereof facing onto a hollow layer formed inside thedouble-glazing unit, an overlapping portion where overlap occurs in adirection perpendicular to mutually facing surfaces of the pair of glassplates, then even in the case that deformation of the pair of glassplates occurs through changes in internal pressure accompanying changesin the temperature of the hollow layer, because the spacer is flexiblein the thickness direction of the double-glazing unit, deformation ofthe joining portions sealing in the hollow layer hardly occurs, andhence dropping of the resistance of the double-glazing unit topenetration of moisture into the hollow layer can be prevented for along time period, and thus the durability performance of thedouble-glazing unit can be improved; moreover, a granular desiccant canbe housed in the spacer.

Moreover, the present inventors discovered that if the gap at theoverlapping portion is not more than 0.6 mm, then even in the case thata desiccant having a very small grain size is used, the desiccant can bereliably housed without falling out from the hollow body, andfurthermore that if the length of the overlapping portion in thethickness direction of the double-glazing unit is not more than a valueobtained by subtracting 2.0 mm from the inside dimension of the hollowbody in the thickness direction of the double-glazing unit, then thespacer can be sufficiently flexed in the thickness direction of thedouble-glazing unit.

The present invention was accomplished based on the above findings.

An embodiment of the present invention will now be described withreference to the drawings.

FIG. 1 is a perspective view of a double-glazing unit body havingtherein a spacer for a double-glazing unit according to an embodiment ofthe present invention.

In FIG. 1, the double-glazing unit body 1 is comprised of adouble-glazing unit 10, and a double-glazing unit holder 20 fitted in atan outer peripheral portion of the double-glazing unit 10. Thedouble-glazing unit 10 is held in a sash 30 by the double-glazing unitholder 20.

FIGS. 2A and 2B are fragmentary sectional views of the double-glazingunit 10 shown in FIG. 1; FIG. 2A is a fragmentary sectional view of theouter peripheral portion of the double-glazing unit 10, and FIG. 2B isan enlarged fragmentary sectional view of the outer peripheral portionof the double-glazing unit 10.

As shown in FIG. 2A, the double-glazing unit 10 is comprised of a pairof glass plates 11 and 12 each of thickness 3.0 mm that face one anotherwith a predetermined gap therebetween, a spacer 13 that is insertedbetween the glass plates 11 and 12 at a peripheral portion thereof so asto fix the predetermined gap between the glass plates 11 and 12 at, forexample, 14.5 mm, and a secondary sealant 16 (sealing portion) that isfilled between the glass plates 11 and 12 on the outside of the spacer13 (on the outer periphery side of the double-glazing unit 10) and sealsthe spacer 13 from the exterior. A hollow layer 14 formed inside thedouble-glazing unit 10 is filled with dry air.

The spacer 13 is comprised of an elongated thin-walled hollow body 13 bthat is interposed via a primary sealant 15 (joining portions) betweenthe pair of glass plates 11 and 12 in the double-glazing unit 10 andhouses a desiccant 13 a. The hollow body 13 b has, at a side thereoffacing onto the hollow layer 14 formed inside the double-glazing unit10, an overlapping portion 13 d where overlap occurs in a directionperpendicular to mutually facing surfaces of the pair of glass plates 11and 12. Moreover, as shown in FIG. 2B, a gap D at the overlappingportion 13 d is not more than 0.6 mm, and a length A of the overlappingportion 13 d in a thickness direction of the double-glazing unit 10(hereinafter merely referred to as the “length A of the overlappingportion 13 d”) is not more than a value obtained by subtracting 2.0 mmfrom an inside dimension E of the hollow body in the thickness directionof the double-glazing unit. The inside dimension E of the hollow body inthe thickness direction of the double-glazing unit 10 is, for example,10 mm.

The elongated thin-walled hollow body 13 b is made of aluminum, has athickness of 0.35 mm, and has material constants of a Young's modulus of7.0×10⁵ kgf/cm², and a Poisson ratio of 0.3.

To make it difficult for moisture to permeate through the primarysealant 15 in particular, the primary sealant 15 is, for example, madeof butyl rubber, has material constants of, for example, a Young'smodulus of 5.0 kgf/cm² and a Poisson ratio of 0.4, and has a thicknessof, for example, 0.25 mm. Moreover, the length of contact at theinterface between the primary sealant 15 and each of the glass plates 11and 12 is 5.0 mm.

The secondary sealant 16 is made, for example, of a highly adhesivesilicone or polysulfide sealant, and has material constants of, forexample, a Young's modulus of 20 kgf/cm² and a Poisson ratio of 0.4.Moreover, the length of contact at the interface between the secondarysealant 16 and each of the glass plates 11 and 12 is 5.0 mm. As aresult, dropping of the resistance to penetration of moisture into thehollow layer 14 can be prevented for a yet longer time period.

Here, as described earlier, expansion and contraction of the primarysealant 15 affects the durability performance of the double-glazing unit10, and hence the durability performance, i.e. lifetime, of thedouble-glazing unit 10 can be evaluated using a strain ratio for theprimary sealant 15.

First, the number of repeated actions until the primary sealant breaks,i.e. the lifetime of the primary sealant under repeated dynamic stressactions, is given by the maximum integer i for which equation (1) issatisfied. In equation (1), σC represents a value representing thestrength of the primary sealant, σL represents a value representing thestress acting on the primary sealant, and n represents a constantcharacteristic of the material.i<(σC/σL)^(n+1)  (1)

Next, let us compare the lifetime for two primary sealants havingdifferent stresses acting thereon. That is, taking σL₁ to be a valuerepresenting the stress acting on the primary sealant in a conventionaldouble-glazing unit as shown in FIG. 4, and taking σL₂ to be a valuerepresenting the stress acting on the primary sealant in thedouble-glazing unit of the present invention, the ratio R of thelifetime for the primary sealant in the double-glazing unit of thepresent invention relative to the primary sealant in the conventionaldouble-glazing unit is given by the following equation.R=(β)^(−(n+1))  (2)

(wherein β=σL₂/σL₁)

By using above equation (2), the increase in the lifetime of the primarysealant in the double-glazing unit of the present invention relative tothe lifetime of the primary sealant in the conventional double-glazingunit can be estimated. For example, setting the material-characteristicconstant n for the primary sealant in equation (2) to be 2, 7 or 16, theresults of plotting the double-glazing unit lifetime ratio against theprimary sealant strain ratio (β) are as shown in FIG. 3.

FIG. 3 is a graph showing the relationship between the primary sealantstrain ratio and the double-glazing unit lifetime ratio.

In FIG. 3, the primary sealant strain ratio is shown on the axis ofabscissas, and the double-glazing unit lifetime ratio is shown on theaxis of ordinates. In FIG. 3, “⋄” shows the relationship between theprimary sealant strain ratio and the double-glazing unit lifetime ratiofor the case that n=2, “□” for the case that n=7, and “◯” for the casethat n=16.

Out of these graphs, in the case, for example, that n=2, if the primarysealant strain ratio is 0.8, then the lifetime of the double-glazingunit is approximately two times, and if the primary sealant strain ratiois 0.6, then the lifetime of the double-glazing unit is approximately4.5 times.

From the above results, it can be seen that by reducing the primarysealant strain ratio to 0.8 or below, the lifetime of the double-glazingunit can be improved by at least two times.

According to the present embodiment, the elongated thin-walled hollowbody 13 b having the desiccant 13 a housed therein has, at a sidethereof facing onto the hollow layer 14 formed inside the double-glazingunit 10, an overlapping portion 13 d where overlap occurs in a directionperpendicular to mutually facing surfaces of the pair of glass plates 11and 12. As a result, even in the case that deformation of the pair ofglass plates 11 and 12 occurs through changes in internal pressureaccompanying changes in the temperature of the hollow layer 14 formedinside the double-glazing unit 10, because the spacer 13 is flexible inthe thickness direction of the double-glazing unit 10, deformation ofthe primary sealant 15 sealing in the hollow layer 14 hardly occurs, andhence dropping of the resistance of the double-glazing unit 10 topenetration of moisture into the hollow layer 14 can be prevented for along time period, and thus the durability performance of thedouble-glazing unit 10 can be improved; moreover, a granular desiccant13 a can be housed in the spacer 13.

According to the present embodiment, the gap D at the overlappingportion 13 d is not more than 0.6 mm. As a result, even in the case ofusing a desiccant 13 a having a very small grain size, the desiccant 13a can be reliably housed without falling out from the hollow body 13 b.

According to the present embodiment, the length A of the overlappingportion 13 d is not more than a value obtained by subtracting 2.0 mmfrom the inside dimension E of the hollow body in the thicknessdirection of the double-glazing unit. As a result, the spacer 13 can besufficiently flexed in the thickness direction of the double-glazingunit 10.

According to the present embodiment, the double-glazing unit 10 hastherein a secondary sealant 16 that is filled between the pair of glassplates 11 and 12 on the outer periphery side of the double-glazing unit10 relative to the spacer 13 and seals the spacer 13 from the exterior.As a result, dropping of the resistance to penetration of moisture intothe hollow layer 14 can be prevented for a yet longer time period.

EXAMPLES

Examples of the present invention will now be described.

As Example 1, an aluminum spacer having an overlapping portion with agap D of 0.0 mm and a length A of 2.0 mm, having an inside dimension Eof the hollow body in the thickness direction of the double-glazing unitof 10 mm, and having a desiccant housed therein was first sandwichedbetween a pair of glass plates each of dimensions 1000 mm×1000 mm, thespacer was bonded to each of the glass plates with a butyl rubberprimary sealant, and then a secondary sealant sealing the spacer fromthe exterior was filled in between the pair of glass plates on the outerperiphery side of the double-glazing unit relative to the spacer, thuspreparing a double-glazing unit. Next, as Example 2, a double-glazingunit was prepared having the same construction as in Example 1 exceptthat a spacer having an overlapping portion with a gap D of 0.3 mm wasused instead of the spacer having an overlapping portion with a gap D of0.0 mm, and furthermore as Example 3, a double-glazing unit was preparedhaving the same construction as in Example 1 except that a spacer havingan overlapping portion with a gap D of 0.6 mm was used.

On the other hand, as Comparative Example 1, a double-glazing unit wasprepared having the same construction as in Example 1 except that aspacer having an overlapping portion with a gap D of 0.8 mm was used.

Next, for each of Examples 1 to 3 and Comparative Example 1,two-dimensional non-linear structural analysis taking into considerationchanges in the volume of the air layer, and a cycle test were carriedout, thus evaluating the durability. Here, in the cycle test, the airpressure was set to 101.3 kPa, the maximum temperature was set to 50° C.and the minimum temperature to −50° C., the time period over which thesample to be tested is kept at each of these temperatures was made to be0.5 hours, and the time period over which the ambient temperature waschanged from the maximum temperature to the minimum temperature and fromthe minimum temperature to the maximum temperature was made to be 3hours; the cycle with the ambient temperature starting from the maximumtemperature, passing through the minimum temperature, and then againreaching the maximum temperature was carried out 300 times.

The evaluation of the durability was carried out through overallevaluation of: primary sealant strain evaluation using two-dimensionalnon-linear structural analysis in which the strain was calculated forthe tip on the air layer side of the primary sealant for each of theExamples and the Comparative Example, taking the strain for the tip onthe air layer side of the primary sealant in the case of using theconventional spacer as standard; and a desiccant check of checkingwhether or not the desiccant was still housed in the spacer after theabove cycle test.

The evaluation results are shown in Table 1. In Table 1, “pass” isrepresented by “◯”, and “fail” by “X>”; likewise hereinafter. TABLE 1Primary Ratio relative Gap D at Length A of sealant to strain foroverlapping overlapping strain conventional Desiccant portion (mm)portion (mm) (%) spacer (%) check Judgment Example 1 0.0 2.0 5.3 49 ◯ ◯Example 2 0.3 2.0 5.3 49 ◯ ◯ Example 3 0.6 2.0 5.4 50 ◯ ◯ Comparative0.8 2.0 5.4 50 X X Example 1

From the results in Table 1, it can be seen that because the elongatedthin-walled hollow body housing the desiccant has, at a side thereoffacing onto the hollow layer formed inside the double-glazing unit, anoverlapping portion where overlap occurs in a direction perpendicular tomutually facing surfaces of the pair of glass plates, even in the casethat deformation of the pair of glass plates occurs through changes inthe internal pressure accompanying changes in the temperature of thehollow layer formed inside the double-glazing unit, because the spaceris flexible in the thickness direction of the double-glazing unit,deformation of the primary sealant sealing in the hollow layer hardlyoccurs, and hence dropping of the resistance of the double-glazing unitto penetration of moisture into the hollow layer can be prevented for along time period, and thus the durability performance of thedouble-glazing unit can be improved; moreover, the granular desiccantcan be housed in the spacer.

Moreover, it can be seen that if the gap D at the overlapping portion isnot more than 0.6 mm, then even in the case of using a desiccant havinga very small grain size, the desiccant can be reliably housed withoutfalling out from the hollow body.

Next, for the double-glazing unit of Example 1, spacers having differentlengths A of the overlapping portion were used, and durability testswere carried out on the resulting double-glazing units.

Specifically, as Example 4, a double-glazing unit was prepared havingthe same construction as in Example 1 except that a spacer having anoverlapping portion with a length A of 0.0 mm was used instead of thespacer having an overlapping portion with a length of 2.0 mm; theoverlapping portion had a gap D of 0.0 mm. Moreover, as Example 5, adouble-glazing unit was prepared having the same construction as inExample 1 except that a spacer having an overlapping portion with alength A of 1.0 mm was used, as Example 6, a double-glazing unit wasprepared having the same construction as in Example 1 except that aspacer having an overlapping portion with a length A of 4.0 mm was used,and as Example 7, a double-glazing unit was prepared having the sameconstruction as in Example 1 except that a spacer having an overlappingportion with a length A of 8.0 mm was used.

On the other hand, as Comparative Example 2, a double-glazing unit wasprepared having the same construction as in Example 1 except that aspacer having an overlapping portion with a length A of 10 mm was used,this being the same as the inside dimension E of the hollow body in thethickness direction of the double-glazing unit.

Next, for Examples 4 to 7 and Comparative Example 2, the durability wasevaluated as for Example 1. The results are shown in Table 2. TABLE 2Primary Ratio relative Gap D at Length A of sealant to strain foroverlapping overlapping strain conventional Desiccant portion (mm)portion (mm) (%) spacer (%) check Judgment Example 4 0.0 0.0 5.0 46 ◯ ◯Example 5 0.0 1.0 5.2 48 ◯ ◯ Example 5 0.0 4.0 5.4 50 ◯ ◯ Example 6 0.08.0 5.8 54 ◯ ◯ Comparative 0.0 10.0 9.2 85 ◯ X Example 2

From the results in Table 2, it can be seen that if the length A of theoverlapping portion is not more than 8.0 mm, then the spacer can besufficiently flexed in the thickness direction of the double-glazingunit.

In the above embodiment of the present invention, the double-glazingunit 10 may be constructed using laminated glass, or three or more glassplates, and moreover may be constructed such that all or some of theglass plates in the double-glazing unit 10 have a function of absorbingheat rays, absorbing ultraviolet rays, reflecting heat rays (possibly asa thermal barrier) or the like, or are wired, tempered or the like.

Moreover, in this embodiment, a pair of glass plates 11 and 12 are usedfor the double-glazing unit 10; the pair of glass plates 11 and 12 maybe any of evacuated glass (e.g. Spacia (registered trademark)),functional glass on which a heat ray-reflecting film has been formed byvapor deposition (e.g. Refshine (registered trademark)), security glasshaving a resin film sandwiched therein (e.g. Secuo (registeredtrademark)), tempered glass for which the surface compressive stress hasbeen increased through heat treatment (e.g. Pyroclear (registeredtrademark)), or the like.

In this embodiment, the hollow layer 14 formed inside the double-glazingunit 10 is filled with dry air; however, there is no limitation thereto,but rather the hollow layer 14 may be filled with an inert gas such asAr.

In this embodiment, the elongated thin-walled hollow body 13 b may havea substantially rectangular cross-sectional shape. As a result, thejoint strength at the primary sealant 15 can be improved. Moreover, thecross-sectional shape of the hollow body 13 b may project out at a sidethereof opposite the overlapping portion 13 d. As a result, the hollowbody 13 b can be reliably flexed. Furthermore, the side opposite theoverlapping portion 13 d in the cross-sectional shape of the hollow body13 b may project out toward the outer periphery of the double-glazingunit 10. As a result, space for housing the desiccant 13 a can bereliably secured.

In this embodiment, the spacer 13 is made of aluminum; however, there isno limitation thereto, but rather the spacer 13 may be made of an alloyhaving aluminum as a principal component thereof. As a result, the gapbetween the pair of glass plates 11 and 12 can be kept approximatelyconstant.

In this embodiment, the primary sealant 15 is made of butyl rubber;however, there is no limitation thereto, but rather the primary sealant15 may be made of any material that makes it difficult for moisture topermeate therethrough. Moreover, the primary sealant 15 has a thicknessof 0.25 mm, but there is no limitation to this value. Furthermore, thelength of contact at the interface between the primary sealant 15 andeach of the glass plates 11 and 12 is 5.0 mm, but there is no limitationto this value.

In this embodiment, the secondary sealant 16 is made of a highlyadhesive silicone or polysulfide sealant, but there is no limitationthereto. Moreover, the length of contact at the interface between thesecondary sealant 16 and each of the glass plates 11 and 12 is 5.0 mm,but there is no limitation to this value.

INDUSTRIAL APPLICABILITY

According to the spacer for a double-glazing unit of the presentinvention, the elongated thin-walled hollow body housing the desiccanthas, at a side thereof facing onto the hollow layer formed inside thedouble-glazing unit, an overlapping portion where overlap occurs in adirection perpendicular to mutually facing surfaces of the pair of glassplates. As a result, even in the case that deformation of the pair ofglass plates occurs through changes in internal pressure accompanyingchanges in the temperature of the hollow layer formed inside thedouble-glazing unit, because the spacer is flexible in the thicknessdirection of the double-glazing unit, deformation of the joiningportions sealing in the hollow layer hardly occurs, and hence droppingof the resistance of the double-glazing unit to penetration of moistureinto the hollow layer can be prevented for a long time period, and thusthe durability performance of the double-glazing unit can be improved;moreover, a granular desiccant can be housed in the spacer.

According to a preferred form of the spacer for a double-glazing unit ofthe present invention, the hollow body has a substantially rectangularcross-sectional shape. As a result, the joint strength at the joiningportions can be improved.

According to a preferred form of the spacer for a double-glazing unit ofthe present invention, the cross-sectional shape of the hollow bodyprojects out at a side opposite the overlapping portion. As a result,the hollow body can be reliably flexed.

According to a more preferred form of the spacer for a double-glazingunit of the present invention, the side opposite the overlapping portionin the cross-sectional shape of the hollow body projects out toward theouter periphery of the double-glazing unit. As a result, space forhousing the desiccant can be reliably secured.

According to a preferred form of the spacer for a double-glazing unit ofthe present invention, the gap D at the overlapping portion is not morethan 0.6 mm. As a result, even in the case of using a desiccant having avery small grain size, the desiccant can be reliably housed withoutfalling out from the hollow body.

According to a preferred form of the spacer for a double-glazing unit ofthe present invention, the length A of the overlapping portion in thethickness direction of the double-glazing unit is not more than a valueobtained by subtracting 2.0 mm from the inside dimension E of the hollowbody in the thickness direction of the double-glazing unit. As a result,the spacer can be sufficiently flexed in the thickness direction of thedouble-glazing unit.

According to a preferred form of the spacer for a double-glazing unit ofthe present invention, the hollow body contains aluminum or an alloyhaving aluminum as a principal component thereof. As a result, the gapbetween the pair of glass plates can be kept approximately constant.

According to a more preferred form of the spacer for a double-glazingunit of the present invention, the hollow body has a thickness of atleast 2 mm. As a result, the spacer can be sufficiently flexed in thethickness direction of the double-glazing unit.

According to the double-glazing unit of the present invention, thespacer thereof is flexible in the thickness direction of thedouble-glazing unit, whereby deformation of the joining portions sealingin the hollow layer hardly occurs. As a result, dropping of theresistance to penetration of moisture into the hollow layer can beprevented for a long time period.

According to a preferred form of the double-glazing unit of the presentinvention, the double-glazing unit has therein a sealing portion that isfilled between the pair of glass plates on the outer periphery side ofthe double-glazing unit relative to the spacer, and seals the spacerfrom the exterior. As a result, dropping of the resistance topenetration of moisture into the hollow layer can be prevented for a yetlonger time period.

1. A spacer for a double-glazing unit joined via joining portionsbetween a pair of glass plates in the double-glazing unit, characterizedby comprising an elongated thin-walled hollow body housing a desiccant,wherein said hollow body has, at a side thereof facing onto a hollowlayer formed inside the double-glazing unit, an overlapping portionwhere overlap occurs in a direction perpendicular to mutually facingsurfaces of the pair of glass plates.
 2. A spacer for a double-glazingunit as claimed in claim 1, characterized in that said hollow body has asubstantially rectangular cross-sectional shape.
 3. A spacer for adouble-glazing unit as claimed in claim 2, characterized in that thecross-sectional shape of said hollow body projects out at a side thereofopposite said overlapping portion.
 4. A spacer for a double-glazing unitas claimed in claim 3, characterized in that the side opposite saidoverlapping portion in the cross-sectional shape of said hollow bodyprojects out toward an outer periphery of the double-glazing unit.
 5. Aspacer for a double-glazing unit as claimed in claim 1, characterized inthat a gap at said overlapping portion is not more than 0.6 mm.
 6. Aspacer for a double-glazing unit as claimed in claim 1, characterized inthat a length of said overlapping portion in a thickness direction ofthe double-glazing unit is not more than a value obtained by subtracting2.0 mm from an inside dimension of said hollow body in the thicknessdirection of the double-glazing unit.
 7. A spacer for a double-glazingunit as claimed in claim 1, characterized in that said hollow bodycontains aluminum or an alloy having aluminum as a principal componentthereof.
 8. A spacer for a double-glazing unit as claimed in claim 7,characterized in that said hollow body has a thickness of at least 2 mm.9. A double-glazing unit characterized by having therein a spacer for adouble-glazing unit as claimed in claim
 1. 10. A double-glazing unit asclaimed in claim 9, characterized by having a sealing portion that isfilled between the pair of glass plates on an outer periphery side ofthe double-glazing unit relative to the spacer, and seals the spacerfrom an exterior.